Thousands of iPhone 6 users claim they have been left holding almost worthless phones because Apple's latest operating system permanently disables the handset if it detects that a repair has been carried out by a non-Apple technician.

Relatively few people outside the tech world are aware of the so-called "error 53" problem, but if it happens to you you'll know about it. And according to one specialist journalist, it "will kill your iPhone".

The issue appears to affect handsets where the home button, which has touch ID fingerprint recognition built-in, has been repaired by a "non-official" company or individual. It has also reportedly affected customers whose phone has been damaged but who have been able to carry on using it without the need for a repair.

But the problem only comes to light when the latest version of Apple's iPhone software, iOS 9, is installed. Indeed, the phone may have been working perfectly for weeks or months since a repair or being damaged.

After installation a growing number of people have watched in horror as their phone, which may well have cost them £500-plus, is rendered useless. Any photos or other data held on the handset is lost - and irretrievable.

Tech experts claim Apple knows all about the problem but has done nothing to warn users that their phone will be "bricked" (ie, rendered as technologically useful as a brick) if they install the iOS upgrade.

Freelance photographer and self-confessed Apple addict Antonio Olmos says this happened to his phone a few weeks ago after he upgraded his software. Olmos had previously had his handset repaired while on an assignment for the Guardian in Macedonia. "I was in the Balkans covering the refugee crisis in September when I dropped my phone. Because I desperately needed it for work I got it fixed at a local shop, as there are no Apple stores in Macedonia. They repaired the screen and home button, and it worked perfectly."

No choice: journalist Antonio Olmos dropped his iPhone while covering the refugee crisis and had to use a local repair shopThe Guardian

He says he thought no more about it, until he was sent the standard notification by Apple inviting him to install the latest software. He accepted the upgrade, but within seconds the phone was displaying "error 53" and was, in effect, dead.

When Olmos, who says he has spent thousands of pounds on Apple products over the years, took it to an Apple store in London, staff told him there was nothing they could do, and that his phone was now junk. He had to pay £270 for a replacement and is furious.

"The whole thing is extraordinary. How can a company deliberately make their own products useless with an upgrade and not warn their own customers about it? Outside of the big industrialized nations, Apple stores are few and far between, and damaged phones can only be brought back to life by small third-party repairers.

"I am not even sure these third-party outfits even know this is a potential problem," he says.

Olmos is far from the only one affected. If you Google "iPhone 6" and "error 53" you will find no shortage of people reporting that they have been left with a phone that now only functions as a very expensive paperweight.

They carried on using the phone, but when they tried to install iOS 9 in November "error 53" popped up. "The error hasn't occurred because I broke my phone (it was working fine for 10 months). I lost all my data because of this error. I don't want Apple to fix my screen or anything! I just want them to fix the 'error 53' so I can use my phone, but they won't!"

Could Apple's move, which appears to be designed to squeeze out independent repairers, contravene competition rules? Car manufacturers, for example, are not allowed to insist that buyers only get their car serviced by them.

California-based tech expert Kyle Wiens, who runs the iFixit website, says this is a major issue. "The 'error 53' page on our website has had more than 183,000 hits, suggesting this is a big problem for Apple users," he told Guardian Money. "The problem occurs if the repairer changes the home button or the cable. Following the software upgrade the phone in effect checks to make sure it is still using the original components, and if it isn't, it simply locks out the phone. There is no warning, and there's no way that I know of to bring it back to life."

He says it is unclear whether this is a deliberate move to force anyone who drops their phone to use Apple for a repair. "All along, Apple's view is that it does not want third parties carrying out repairs to its products, and this looks like an obvious extension of that," he says. "What it should do is allow its customers to recalibrate their phone after a repair. Only when there is a huge outcry about this problem will it do something."

The Daily Dot website features an article by tech writer Mike Wehner headlined "Error 53 will kill your iPhone and no one knows what it is". He relates how his own iPhone 6 Plus was left "effectively dead to the world".

Meanwhile, an article by tech writer Reuben Esparza, published in November by iCracked, a phone repair service, states: "When pressed for more information about the error, few, if any Apple employees could offer an explanation. There was no part they would replace, no software fix, and no way to access the phone's memory. The fix was a new iPhone." It continues: "Though still largely a mystery to most, we now know that error 53 is the result of a hardware failure somewhere within the home button assembly."

A spokeswoman for Apple told Money (get ready for a jargon overload): "We protect fingerprint data using a secure enclave, which is uniquely paired to the touch ID sensor. When iPhone is serviced by an authorized Apple service provider or Apple retail store for changes that affect the touch ID sensor, the pairing is re-validated. This check ensures the device and the iOS features related to touch ID remain secure. Without this unique pairing, a malicious touch ID sensor could be substituted, thereby gaining access to the secure enclave. When iOS detects that the pairing fails, touch ID, including Apple Pay, is disabled so the device remains secure."

She adds: "When an iPhone is serviced by an unauthorized repair provider, faulty screens or other invalid components that affect the touch ID sensor could cause the check to fail if the pairing cannot be validated. With a subsequent update or restore, additional security checks result in an 'error 53' being displayed … If a customer encounters an unrecoverable error 53, we recommend contacting Apple support."